Motor unit of hand blender

ABSTRACT

A hand blender comprises a motor unit and a tool unit. The motor unit comprises a motor unit coupling part for coupling the tool unit to the motor unit. The tool unit will be coupled onto the motor unit via the motor unit&#39;s motor unit coupling part and the tool unit&#39;s tool unit coupling part. Coupling of the tool unit directly onto the end part of motor reduces the tolerance along the longitudinal axis of the motor unit. Reduction of tolerance is advantageous as it reduces vibration and noise and as it reduces the load on the coupling parts.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is a continuation of co-pending U.S. patentapplication Ser. No. 14/899,189, filed Dec. 17, 2015, which is the U.S.National Phase application under 35 U.S.C. § 371 of InternationalApplication No. PCT/EP2014/062874, filed on Jun. 18, 2014, which claimsthe benefit of International Application No. 13174346.0 filed on Jun.28, 2013. These applications are hereby incorporated by referenceherein.

FIELD OF THE INVENTION

The invention relates to a motor unit for in arrangement with a toolunit comprising a motor, and an end part positioning the motor shaft ona longitudinal axis of the motor.

The invention relates to a hand blender comprising a tool unit and amotor unit as well.

BACKGROUND OF THE INVENTION

Conventional hand blenders comprise of a motor unit and severalseparable tool unit. Tool units are used for food processing such ascutting, chopping and blending. The motor drives a tool member, such asa chopper, cutter or blender, via the motor drive shaft, the couplingassembly and the tool drive shaft. The transfer of rotational movementfrom the motor shaft to the tool member and the transfer of axial,tangential and radial forces from the tool member to the motor shaft,due to the forces invoked by the processing of food, on top oftolerances due to material and geometric properties, lead to marginsbetween the several elements of the hand blender. The design of twoseparable elements introduces an extra source of margin in the totaltolerance chain of the hand blender. Tolerance causes noise andvibration, results in power loss and may lead to wear, damage and earlyfailure.

OBJECT OF THE INVENTION

It is an object of the invention to reduce the tolerance between themotor unit and the tool unit of a hand blender.

SUMMARY OF THE INVENTION

In the motor unit according to the invention the end part furthercomprises a motor unit coupling part for coupling the tool unit to themotor unit. The tool unit will be coupled onto the motor unit via themotor unit coupling part and the tool unit's tool unit coupling part.The tool unit is coupled such that it is connected to the motor unit andthat the tool unit follows the motion of the motor unit. Coupling of thetool unit directly onto the end part of motor reduces the tolerancealong the longitudinal axis of the motor unit because the end part holdsboth the bearing positioning the motor shaft and the motor unit couplingpart. Reduction of tolerance is advantageous as it reduces vibration andnoise and as it reduces the load on the coupling parts.

The end part of the motor according to the invention preferablycomprises an alignment zone for aligning the tool unit to the motor. Thealignment zone for guiding and aligning the tool unit shaft guides thetool unit shaft in an axial and radial direction when a user mounts thetool unit onto the motor unit and aligns the tool drive shaft in aradial direction onto the motor drive shaft. Then the radial offsetbetween the tool unit shaft and the motor drive shaft is minimizedbecause the end part also positions the motor drive shaft. This isbeneficial as the alignment zone for guiding and aligning reduces theradial tolerance between the tool unit and the motor. Tolerancereduction has a positive effect on the lifetime of among others themotor bearing, motor drive shaft and coupling components.

In another embodiment the motor unit coupling part comprises thealignment zone. Location of the alignment zone for guiding and aligningin the motor unit coupling part reduces the tolerance between the motorunit and the tool unit.

Positioning this aligning zone on the motor unit coupling part of theend part ensures that alignment is effected when coupling the motor unitto the tool unit.

Conveniently the end part comprises a fixating zone for fixating thetool unit to the motor. The fixating zone further enhances thepositioning of the tool unit relative to the motor unit.

In another embodiment the motor unit coupling part comprises thefixating zone. Locating the fixating zone for fixating into the motorunit coupling part reduces the tolerance between the motor unit and thetool unit. Positioning this fixating zone on the motor unit couplingpart of the end part further ensures that fixation is effected whencoupling the motor unit to the tool unit.

Preferably the end part comprises a locking zone for locking the toolunit to the motor unit. The purpose of the locking zone for locking thetool unit is to prevent release of the tool unit in an axial directionfrom the motor unit. In use the tool unit is fixed in an axial directionto the motor unit using this locking zone thus ensuring that the motordrive shaft remains coupled to drive the tool drive shaft. This transferenables the hand blender to process food. The locking zone enables themotor unit to release the tool unit when the user operates a releasebutton.

In a preferred embodiment the motor unit coupling part comprises thelocking zone. Location the locking zone in the motor unit coupling partis advantageous as it enables a more compact design. Users prefer acompact design.

Conveniently, the end part comprises a seal at an outer end of the endpart. The sealing zone for sealing is advantageous at the outer end ofthe end part as the sealing zone may hinder food or water to enter themotor unit. When a user makes a mess of the food processing or when auser cleans the motor unit under streaming water, the sealing zone forsealing prevents the food or water from entering the motor unit. Havingthe seal at the outer end of the end part ensures that the seal isproperly aligned.

Furthermore the end part according to the invention contributes to noisereduction, vibration reduction, a decrease of power loss and a lesscomplicated design.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other aspects of the motor unit and hand blender of theinvention will be further elucidated and described with reference to thedrawings in which

FIG. 1A depicts a side elevation of a hand blender with a first toolunit coupled to the blender motor unit;

FIG. 1B depicts a side elevation of the hand blender of FIG. 1A nowcoupled with a second tool unit;

FIG. 2 depicts the interior of a motor unit according to the inventionin a perspective view;

FIG. 3 depicts a motor unit according to the invention and a part of atool unit according to the invention in a perspective view;

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A presents a side view of a hand mixing device or hand blender 1.The hand blender 1 comprises a motor unit 2 and a tool unit 3 that iscoupled to the motor unit 2 by means of a coupling assembly (notvisible). The motor unit 2 houses a motor (not shown) for driving thetool unit 3. The tool unit 3 is coupled such that it is connected to themotor unit 2 and that the tool unit 3 follows the motion of the motorunit 2: for example, when a user lifts the motor unit 2, because of theconnection, the tool unit is lifted as well. The hand blender 1 isgenerally used as a kitchen appliance and can be used in the preparationof food. The tool unit 3 is detachably coupled to the motor unit 2 bymeans of a coupling assembly (not visible) of which one pushbuttons 4 aand 4 b, with which decoupling of the tool unit 3 and the motor unit 2can be effected, are just visible. The motor unit 2 of the hand blender1 further comprises control buttons 5, 6 with which a user can forexample turn on and off the hand blender 1 and/or can control the speedof the hand blender 1. The tool unit 3 comprises a tool member, such asa cutting knife, which is at the lower end of the tool unit 3 and whichmay be used to cut food.

In the example of FIG. 1A the tool unit 3 is a so-called bar blender.Other tool units having different functions can also be coupled to themotor unit 2 by means of the coupling assembly. FIG. 1B gives an exampleof such another tool unit 3 a which is known as a chopper.

FIG. 2 presents a perspective view of the interior of a motor unit 2according to the invention, while FIG. 3 presents a perspective view ofthe interior of a motor unit 2 according to the invention together witha part of a tool unit 3 according to the invention. The interior of themotor unit 2 houses an electric drive motor 20 which is coupled to andarranged for driving a motor drive shaft (not shown). The drive motormay be battery-powered or may be powered by mains. At one end of thedrive motor 20 an end part 21 may be connected to the drive motor 20. Anexample of an end part is a motor shield. A motor shaft (not shown) isarranged in the motor 20 along longitudinal axis L. Conventionally aradial bearing (not shown) is located in the end part 21. The radialbearing is arranged in the end part around the motor shaft (not shown)to support the motor drive shaft (not shown) in a radial direction. Themotor 20, the motor drive shaft (not shown), the end part 21 and theradial bearing (not shown) are arranged around the longitudinal axis L.A tool drive shaft (not shown) is arranged in the tool unit 3 totransfer the rotational forces invoked by the motor to a tool (notshown) for food processing. The motor drive shaft (not shown) isarranged to drive the tool drive shaft (not shown) of the tool unit 3.

The end part 21 according to the invention comprises a alignment zonefor guiding and aligning a tool unit 23. The alignment zone for guidingand aligning the tool unit 23 is an alignment zone which guides the toolunit coupling part 32 to the motor unit coupling part 22 in radial andin axial direction. The alignment zone for guiding and aligning the toolunit 23 is shaped as an axisymmetric tube of which the axis of symmetryis the longitudinal axis L. The tool unit 3, including the tool unitcoupling part 32, may be inserted into the alignment zone for guidingand aligning the tool unit 23. When inserting the tool unit 3 into thealignment zone for guiding and aligning the tool unit 23, the tool unitcoupling part 32 moves towards the motor unit coupling part 22 in theend part 21 of the motor unit 2. The zone for aligning and guiding thetool unit (not shown) comprises a first motor unit coupling part (notshown). The first motor coupling surface (not shown) of the alignmentzone for guiding and aligning the tool unit (not shown) has anaxisymmetric shape, for example round.

The tool unit coupling part 32 has a first tool coupling surface 35having a similar axisymmetric shape as the first motor coupling surface(not shown), such that the tool unit coupling part 32 may fit in themotor unit coupling part 22. The shapes of the first tool couplingsurface (not shown) and the first motor coupling surface 35 arecompatible. The shape of the alignment zone for guiding and aligning thetool unit 23 guides the tool unit 3 in an axial direction towards themotor unit, such that the tool unit coupling part 32 and the motor unitcoupling part 22 may contact each other. Translation along thelongitudinal axis L is still possible. Furthermore the shape of thealignment zone for guiding and aligning the tool unit 23 guides andaligns the tool unit in the radial direction such that the longitudinalaxis of the tool unit overlaps the longitudinal axis of the motor unitL. The tool unit may rotate around the longitudinal axis L, but atransformation in a radial direction with respect to the longitudinalaxis L is not possible.

In a preferred embodiment the second motor coupling surface 26 of theend part 21 is arranged to fixate the tool unit 3 in a tangentialdirection. Fixating the tool unit 3 in a tangential direction reducesthe tolerance in a tangential direction, thus reducing noise andvibration in the hand blender 1 and reducing damage and wear of the handblender 1. To properly fixating the tool unit 3, a non-axisymmetricprofile is applied onto the second motor coupling surface 26,non-axisymmetry with respect to the longitudinal axis L. On the toolunit 3 a similar non-axisymmetric profile is applied onto the secondtool coupling surface 36, such that the tool unit coupling part 32 mayfit in the motor unit coupling part 22. The non-axisymmetric profile maybe any shape which enables the tool unit 3 to fixate in a tangentialdirection onto the motor unit 2, such as a n-gon, where n is larger than2, or a round shapecomprising one protrusion. The shapes of the secondtool coupling surface 36 and the second motor coupling surface 26 arecompatible.

When a user turns on the hand blender 1, the motor 2 is started and themotor drive shaft (not shown) starts rotating. By means of the couplingassembly, a joint between the motor unit coupling part 22 and the toolunit coupling part 32, the rotation is transferred to the tool driveshaft (not shown). The tool drive shaft drives the tool member (notshown). The alignment zone for guiding and aligning a tool unit 3 andthe fixating zone for fixating a tool unit 3 enable the motor driveshaft (not shown) to transfer the rotation to the tool drive shaft (notshown) without tolerance. The harmony between the motor couplingsurfaces (not shown) 24,26 and the tool coupling surfaces 35, 36 reducethe overall margin between the tool member and the motor 20 and thusreduce the amount of vibration and noise, power loss and damage andwear.

A locking zone 27 for locking the tool unit 3 may be arranged on the endpart 21 as well. The objective of the locking zone 27 for locking thetool unit 3 is to hinder movement of the tool unit 3 with respect to themotor unit in an longitudinal direction L. The locking zone 27 forlocking the tool unit comprises a knob 28. The tool unit 3 comprises agroove 38. The knob 28 is connected to a protrusion (not shown) which isarranged to fit into the groove 38. If the tool unit coupling part 32 isconnected to the motor unit coupling part 22 and the tool unit 3 isaxially aligned to the motor unit 2, the protrusion (not shown) slidesinto the groove 38, thus locking the tool unit in an axial direction. Tounlock the tool unit 3 and to remove the tool unit 3 from the motor unit2, a user needs to push the knob 28 to release the protrusion (notshown) from the groove 38.

At the outer end of the end part 21 which is not connected to the motor20 a sealing zone for sealing 29 may be provided. The sealing zone forsealing 29 prevents that foreign material, such as food or water, entersthe end part 21. When the tool unit 3 is connected to the motor unit 2,the sealing zone for sealing 29 closes off the radial tolerance betweenthe tool unit 3 and the motor unit 2 at the outer end of the end part21.

FIGS. 2 and 3 show a preferred embodiment of the invention wherein thetool unit coupling part 32 is arrangeable in the motor unit couplingpart 22. However, in another embodiment the motor unit coupling part 22may be designed such that the motor unit coupling part 22 is arrangeablein the tool unit coupling part 32.

1. A hand blender comprising: a tool unit, wherein the tool unitcomprises a tool unit coupling part that includes a first tool unitcoupling surface; and a motor unit for use in arrangement with the toolunit, wherein the motor unit comprises (i) a motor that comprises amotor shaft, and (ii) an end part for positioning the motor shaft on alongitudinal axis of the motor, wherein the end part further comprises amotor unit coupling part arranged to be coupleable to the tool unitcoupling part of the tool unit, wherein the motor unit coupling partcomprises at least one of (a) an alignment zone for aligning the toolunit to the motor and (b) a fixating zone for fixating the tool unit tothe motor, wherein the alignment zone includes an axisymmetric couplingcomponent with a first motor unit coupling surface, wherein the firstmotor unit coupling surface has an axisymmetric shape and the first toolunit coupling surface has a compatible axisymmetric shape similar tothat of the first motor unit coupling surface, such that the tool unitcoupling part mounts onto the motor unit coupling part and is guided inan axial direction towards the motor unit, wherein the axisymmetricshape of the first tool unit coupling surface guides and aligns the toolunit in the radial direction such that a longitudinal axis of the toolunit overlaps the longitudinal axis of the motor unit, and wherein thefixating zone includes a second motor unit coupling surface of theaxisymmetric coupling component, wherein the second motor unit couplingsurface has a non-axisymmetric profile that is non-axisymmetric withrespect to the longitudinal axis, and wherein the tool unit couplingpart further includes a second tool unit coupling surface, the secondtool unit coupling surface having a compatible non-axisymmetric profilesimilar to that of the second motor unit coupling surface, such that thetool unit coupling part further mounts onto the motor unit couplingpart, via the second tool unit coupling surface and second motor unitcoupling surface, respectively, to fixate the tool unit in a tangentialdirection in response to the second tool unit coupling surface beingcoupled with the second motor unit coupling surface.
 2. The hand blenderaccording to claim 1, wherein the axisymmetric coupling componentcomprises an axisymmetric tube with the first motor unit couplingsurface, wherein the tool unit coupling part fits in the motor unitcoupling part and is guided in an axial direction towards the motorunit, and wherein the tool unit may rotate, via the first tool unitcoupling surface and first motor unit coupling surface, respectively,about the longitudinal axis, but movement in a radial direction withrespect to the longitudinal axis is not possible,
 3. The hand blenderaccording to claim 1, wherein the alignment zone of the motor unitcoupling part is positioned within the end part closer to the motor thanthe fixating zone.
 4. The hand blender according to claim 3, wherein theaxisymmetric coupling component comprises an axisymmetric tube with thefirst motor unit coupling surface, wherein the tool unit coupling partfits in the motor unit coupling part and is guided in an axial directiontowards the motor unit, and wherein the tool unit may rotate, via thefirst tool unit coupling surface and first motor unit coupling surface,respectively, about the longitudinal axis, but movement in a radialdirection with respect to the longitudinal axis is not possible,
 6. Thehand blender according to claim 1, wherein the non-axisymmetric profilecomprises a shape selected from the group consisting of (i) an n-gon,where n is larger than 2, and (ii) a round shape comprising oneprotrusion.
 6. The hand blender according to claim 1, wherein the endpart further comprises a locking zone for locking the tool unit to themotor unit.
 7. The hand blender according to claim 6, wherein the motorunit coupling part comprises the locking zone.
 8. The hand blenderaccording to claim 1, wherein the end part further comprises a sealingzone for sealing at an outer end of the end part.
 9. The hand blenderaccording to claim 1, further wherein the tool unit coupling part isarrangeable in the motor unit coupling part.
 10. The hand blenderaccording to claim 1, further wherein the motor unit coupling part isarrangeable in the tool unit coupling part.